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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Biochemical characterization of serologically detected human melanoma antigens was undertaken for the development of immunodiagnostic assays in melanoma. An antiserum from a human melanoma patient, which detected melanoma antigens expressed on a large proportion of different melanoma cells, was used in leucocyte-dependent cytotoxic antibody (LDA) 51Cr-release assays to monitor the purification of melanoma antigens in urea/acetate extracts of lactoperoxidase 125I-labelled melanoma cell membranes. The separation procedures included affinity chromatography on Concanavalin A, gel filtration on porous polyacrylamide beads and preparative isoelectric focusing. The fractions were also monitored by polyacrylamide electrophoresis in sodium dodecyl sulphate and by measurement of beta 2 microglobulin and carcinoembryonic antigen content. The antigens detected by this antiserum appeared to be acidic (pI 3.5) low-mol.-wt glycoproteins of approximately 15,000 daltons which were resistant to heating at 56 degrees C and digestion with neuraminidase, but susceptible to repeated freeze-thawing and trypsin digestion. They did not appear to be related to HLA antigens, beta 2 microglobulin or known foetal antigens. The nature of the antigens detected in these studies is as yet unknown, but they appear similar to those described in the sera and urine of melanoma patients in previous reports. Thes combined results and the frequent expression of these antigens on melanoma cells from different patients suggest that assays to detect this antigen may provide a valuable immunodiagnostic aid in the management of melanoma.
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PMID:Detection of a low-molecular-weight antigen on melanoma cells by a human antiserum in leukocyte-dependent antibody assays. 9 79

Guinea-pig melanocytes in mixed epidermal cell cultures bind melanocyte-stimulating hormone in a distinct focal surface area in their perinuclear field and thus follow the same pattern previously described for Cloudman melanoma cells. The labeling index ranged from 18 to 34%. Pretreatment of cultures with trypsin leads to destruction of melanocyte-stimulating hormone receptors whereas neuraminidase has no such effect.
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PMID:Melanocyte-stimulating hormone receptors on cultured guinea-pig melanocytes. 18 12

Lipid-bound sialic acid in the murine melanoma cell is not totally inaccessible to an exogenous macromolecular probe, as formerly believed. Roughly 30% of the dialic acid bound to lipid, and an equal proportion of the sialic acid bound to protein is cleaved by the action of Clostridium perfringens N-acetylneuraminate glycohydrolase (neuraminidase, sialidase) when the purified enzyme is added to the suspenion medium of intact murine melanoma cells freshly derived from the tumor. Cleavage of lipid-bound sialic acid is indifferent to the presence of Ca (2+) in the medium. However, maximum release from protein requires a physiological concentration of this divalent cation. Variation in ionic strength has no effect on release of sialic acid. These findings show that restricted portion of the bound sialic acid may be released from the intact murine melanama cell by the extracellularly supplied enzyme acting topographically.
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PMID:Accessibility of sialo components in a murine tumor cell to extracellular N-acetylneuraminate glycohydrolase (sialidase). 22 20

Two forms of therapy employed for treatment of patients with recurrent melanoma limited to the extremity, and carried out during different intervals of time, are presented. Perfusion of the involved extremity with phenylalanine mustard has resulted in a 5-year survival rate of 28% of 43 patients. A second group of 25 patients has been treated by a four-stage immunotherapy program consisting of sensitization with intradermal BCG, followed in 6 weeks by intra tumor injection of BCG. A third stage involved the activation of the patients's lymphocytes, after removal by a blood cell separator, incubated in vitro with irradiated neuraminidase-treated melanoma cells and reintroduced into the patient either by subcutaneous or intratumor injection. The fourth stage of immunotherapy involves injection of an inoculum of irradiated neuraminidase-treated autochothonous tumor cells plus BCG injected intratumorally or subcutaneously. Sixteen of 24 patients receiving immunotherapy treatment program have experienced arrest of their disease lasting from 5 to 42 months.
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PMID:Management of recurrent melanoma of the extremity. 23 93

Cell surface glycoproteins of human tumor cell lines (melanomas and astrocytomas, and ovarian, bladder, stomach, cervical, laryngeal, and renal cancers) were studied by labelling with 1) neuraminidase-galactose oxidase-[3H]borohydride, 2) galactose oxidase-[3H]borohydride, and 3) dilute periodate-[3H]borohydride. The labeled components were examined by polyacrylamide gel electrophoresis and fluorography. Each tumor type had a distinctive pattern of labeled glycoproteins when the results from both procedures 1 and 2 were considered. Cell surface glycoproteins of malignant melanoma could not be labeled by procedure 2, whereas the other cell lines had at least two major glycoproteins that could be labeled by this method. Very similar profiles of melanoma glycoproteins were labeled by procedures 1 and 3. From these results the conclusion was reached that cell surface glycoproteins of melanomas are substituted with sialic acid so that their D-galactose and/or N-acetyl-D-galactosamine residues are available for oxidation by galactose oxidase only after neuraminidase treatment. An alternative explanation that these sugars are sterically accessible to galactose oxidase only after neuraminidase treatment also has to be considered. All melanoma lines studied were characterized by having two major cell surface glycoproteins with molecular weights of 110,000 and 90,000, respectively. Lines, however, varied considerably in their expression of other components. In particular, heterogeneity was shown in the expression of gp220, a component identified as fibronectin by immunoprecipitation with a specific antiserum, and in the expression of gp37/32, a pair of glycoproteins having the characteristics of la-like antigens. Of the other cell lines studied, astrocytomas most closely resembled melanoma in their glycoprotein profiles. The brain tumors, however, had two or three glycoproteins, including gp110, which could be labeled by galactose oxidase-[3H]borohydride without neuraminidase treatment.
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PMID:Cell surface glycoproteins of human tumor cell lines: unusual characteristics of malignant melanoma. 38 52

B16 melanoma cells were treated in vitro with muconomycin A, a long-lasting inhibitor of protein and glycoprotein synthesis, to reduce cellular sialic acid. Two i.p. inoculations of 10(7) muconomycin-treated cells into female C57BL/6 mice, followed by challenge with homologous live cells, resulted in a significant decrease in tumor incidence when compared to the results of inoculation with untreated cells (p less than 0.01). Inoculation of mice with cells treated with neuraminidase resulted in little or no decrease in tumor incidence. Effective immunity was dependent on the number of cells injected and was found only with the i.p. route of inoculation into female mice.
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PMID:Increased tumor immunity in mice inoculated with muconomycin A-treated B16 melanoma cells. 69 27

Electrophoretic studies on malignant melanoma extracts before and after treatment with neuraminidase revealed that tyrosinase is a glycoprotein containing N-acetyl-neuraminic acid. Double diffusion tests using Concanavalin A and the lectin from Ricinus communis show that the carbohydrated chain of tyrosinase contains D-mannose as a sugar unit located within the carbohydrate chain. The terminal neuraminic acid groups are linked to D-galactose. The enzymatic activity of tyrosinase is not inhibited by Concanavalin A.
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PMID:Demonstration of carbohydrate structures in malignant melanoma tyrosinase. 81 68

A chimpanzee anti-human melanoma antiserum was used to study the enzymatic susceptibility and spontaneous release into tissue culture medium of human melanoma tumor-associated antigens (TAA). Limited proteolytic digestion of melanoma cells with trypsin or with pronase rendered these cells refractory to lysis by the chimpanzee antiserum and complement. Longer periods of incubation of higher concentrations of enzyme caused an increased sensitivity to lysis. Digestion of melanoma cells with neuraminidase apparently exposed antigens reactive with natural antibodies in rabbit complement because cells so treated had a marked increase in sensitivity to cytolysis. Absorption of the complement with either neuraminidase-treated human melanoma cells or washed human spleen cells prior to its use in the cytotoxicity assay removed this activity. When absorbed complement was used, neuraminidase had no noticeable effect on the expression of malanoma TAA. These results suggest that proteolytic digestion of melanoma cells may prove to be a useful means of solubilizing TAA. The spontaneous release of melanoma cell membrane TAA was studied. Protein precipitated by (NH4)2SO4 from four of six samples of tissue culture medium used to feed malanoma cell lines contained significant antigenic activity compared to a control "antigen" preparation, whereas one preparation contained only limited TAA activity. One melanoma cell line that apparently failed to release TAA into the culture medium had previously become nonreactive with the chimpanzee antiserum. From these data, we conclude that melanoma cells growing in tissue culture rapidly release large amounts of TAA into the culture media and, as a result, the spent culture medium may be a good source for obtaining TAA for further study. The significance of these results is discussed.
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PMID:Enzymatic susceptibility and spontaneous release of human melanoma tumor-associated antigens. 83 72

Several agents were compared for their ability to inhibit protein synthesis for long periods in tumor cells growing in culture. Mouse B16 melanoma cells, treated with high concentrations of cycloheximide or pactamycin for 1 hour and then washed repeatedly, recovered their ability to incorporate [3H]leucine into protein in about 4 hours, while cells treated with emetine recovered in 12 hours. After similar treatment with muconomycin A, however, incorporation of [3H]leucine remained inhibited for at least 30 hours. During this time the cells remained attached to the culture dishes, were able to exclude trypan blue dye, and retained nearly normal levels of rubidium-86 content. When another, untreated, population of cells was added to the muconomycin-treated cells, protein synthesis was not inhibited in the untreated population; action of the drug was thus shown to be confined to the treated cells. In melanoma cells treated with neuraminidase and muconomycin, measurement of glycoprotein synthesis (as determined by sialic acid analysis) showed that muconomycin also inhibited restoration of sialic acid content. Brief treatment with muconomycin, therefore, appeared to be sufficient for prolonged inhibition of protein and glycoprotein synthesis.
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PMID:Prolonged inhibition of protein and glycoprotein synthesis in tumor cells treated with muconomycin A. 83 56

B16 melanotic tumors in various organs of mice were labeled with either [14C- or [3H]L-fucose or D-glucosamine. Glycopeptides derived from the membrane glycoproteins of these tumors were compared with those of normal tissues by double-label elution patterns from Sephadex G-50 columns. A marked increase of sialic acid-rich, fucose-containing glycopeptides (PEAK A) was found in the glycoproteins of the surface and internal membranes of melanotic cells. The glycopeptides from the melanoma cells could be reduced in size by treatment with neuraminidase. Comparison of the glycopeptide patterns of melanoma cells grown in culture and in mice revealed a greater complexity in in vivo material. Virtually all of the glycopeptides from melanoma cells grown in culture were of the larger type (Peak A) that correlates well with the malignant state. Comparison of two lines of B16 melanoma cells with greatly differing abilities to form tumors in lung revealed no significant, reproducible differences in their glycopeptide patterns.
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PMID:The surface glycoproteins of a mouse melanoma growing in culture and as a solid tumor in vivo. 116 67


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